I concur with this assessment that this is exactly how the vapor recovery system should work, albeit, if its working properly.
Taking a nice Sunday afternoon drive today in my 1995 Honda civic, and I can swear I can see styling cues in this car reminiscent to that of the GTV, I'm willing to bet Giugiaro had his hand in designing it, GTV from the rear, Bugatti from the front, minus the overstated Alfa 'Scudetto', sufficing with a tiny, almost upside down 'H' for Honda. I know Giugiaro hated car makers grille ideologies. But I always thought it neat to have that brazzen Alfa scudetto charging the front of my car, what better thing to have with you when going into battle, or in this day and age, braving aggressive driving and traffic on the turnpike. 'Get out of my way!' Anyway, during my leisurely drive, I couldn't understand why you heard gurgling in the tank. I mean we know the tank got hot, but I can't imagine the fuel was boiling. So I thought back to the fuel pump. Perhaps its pulling in air and pumping fuel and air back into the tank? Hmmm, pumping fuel backwards into the tank instead of to the SPICA pump. That would explain why the fuel pressure light would take longer to come on and only after the fuel pump has gotten hot enough to have expanded whatever metal and plastic that there is there, breaking some diaphragm or 'O' ring seal, sucking in air. I don't know. But it would explain the gurgling sound you heard, air being blown-in from the bottom of the tank. And just to add and not to offend, I know why you don't think its the fuel pump, because the guy who sold you this $400 pump, told you its not the pump! Probably because he doesn't want to refund your money. And you can't fathom having spent 400 bucks on a pump that is probably defective, or doesn't work correctly. I know, its happened to me. I mean who knows, maybe its not the pump. But if you can get your hands on an older styled pump, well, I think it would be worth the try. John T-Mobile, America's First Nationwide 4G Network Sent by Samsung Mobile -------- Original message -------- Subject: Re: [alfa] over pressurized fuel tank at the track From: [email protected] To: [email protected],Bruce Giller <[email protected]> CC: Bruce Giller wrote: > Date: Sun, 29 Jul 2012 11:01:14 -0400 > From: Bruce Giller <[email protected]> > Subject: Re: [alfa] over pressurized fuel tank at the track to paraphrase, "misery, misery, oh misery," on the topic of fuel tank pressure. I am -not- a fuel system adept, but as I recall the function of the fuel vapor recovery system, it is to -recycle- the fuel vapors and burn them. As I recall (to put a huge disclaimer on it), the vapor canister takes air returning from the engine environment, passes it through the canister's carbon, which adsorbs the fuel. There is a finite capacity for fuel, which is far exceeded when there is liquid fuel in this canister. During running, there is supposed to be an air flow through the canister to purge it of fuel so that its capacity to adsorb fuel is restored for the next idle period. It was my understanding, limited though it be, that a significant overpressure condition should not happen and that the fuel tank should actually be under only very slight pressure, or even a slight vacuum. There should be a power-actuated solenoid valve somewhere (-perhaps- in the vacuum servo channel) which opens to allow air to pass through this canister en route to the intake manifold. If such a path does not exist, then I would understand the thing malfunctioning. I would not understand where any additional air is coming from, but I do have experience with gas cans being filled in cool weather, then bulging nearly to the point of bursting the seams when heated up. One has the partial pressure of the trapped air plus the vapor pressure of the fuel summing to normal atmospheric pressure at cold fill, then the fuel vapor pressure rising significantly as the fuel heats. If there is a one-way path for bleeding the tank through the canister to the intake manifold in parallel with a one-way path from the control valve air intake through the canister, then the canister will be purged during running conditions, any overpressure in the tank will slowly be pumped through the engine and burned. There should be a flow-limiting orifice, which may possibly be just the length of small-diameter tubing connecting things over many feet of path (the Bosch Spider spark advance system is flow-limited in this way so that a leak in the capacitance manometer behind the right rear wall panel does not overwhelm the air metering). Some of this may be misplaced due to the limited number of neurons I have attached to this issue, but a good study on the function and theoretical flow of this system may tell you in short order what is wrong. Michael -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected] -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
